Telecommunication companies running PSTNs (Public Switched Telephone Networks) and PLMNs (Public Land Mobile Networks) are in the business of providing communication services and in doing so are providing increasing built-in intelligence in the form of "IN services" such as 800 number services and call forwarding. In contrast, the World Wide Web (WWW), which has seen explosive growth in recent times, is an example of an Internet-based global network providing complex information services. These two worlds, that of the large communications utilities and that of the highly dynamic, pioneer-spirit WWW information culture, are uneasy companions and each plans to encroach on the domain previously occupied by the others; thus telephony services will be offered over the WWW and information services over the public communication infrastructure.
The present invention proposes technologies for a more synergetic relationship between these two worlds than is currently envisaged and in order to place the present invention in context, a review will first be given of each of these two worlds.
Telephone Networks with IN Services
The Basic PSTN. The basic service provided by a PSTN (Public Switched Telephone Network) is the interconnection of two telephones (that is, setting up a bearer channel between the telephones) according to a called-party telephone number input at the calling-party telephone. FIG. 1 is a simplified representation of a PSTN providing such a service. In particular, customer premises equipment, CPE, 10 (such as standard analogue telephones, but also more recently ISDN terminals) are connected through an access network 11 to switching points, SPs 12. The SPs 12 form nodes in an inter-exchange network 13 made up of interconnecting trunks 14 and SPs that are controlled by control entities 15 in the SPs. The control effected by the control entities 15 is determined by signalling inputs received from the CPEs and other SPs, and involves call setup, maintenance and clearance to provide the desired bearer channel between calling CPE and called CPE. Conceptually, the PSTN may be thought of as a bearer network and a control (signalling) network, the function of the latter being to effect call control through the bearer network, namely the control of setup, maintenance and take down of bearer channels through the bearer network; in practice, the bearer and signalling networks may use the same physical circuits and even the same logical channels.
Thus, where the CPE is a traditional dumb telephone, control signalling between the CPE and its local SP is in-band signalling, that is, the signalling is carried on the same channel as used for voice; this signalling is interpreted and converted at the SPs 12 into signalling between SPs that uses a dedicated common-channel signalling network 16 (implemented nowadays using the SS7 protocol suite). Where the CPE is an ISDN terminal, signalling is carried in a separate channel directly from the CPE on an end-to-end. Modern SPs use the ISUP (ISDN User Part) SS7 protocol for inter-exchange call control signalling whether the CPE is a standard telephone or an ISDN terminal.
Intelligent Networks. In addition to basic call handling, an SP may also serve to provide what are called IN (Intelligent Network) services; in this case the SP is termed a service switching point, SSP. An SSP 25 is arranged to suspend call processing at defined points-in-call upon particular criteria being met, and to delegate the continuation of call processing to a service control subsystem providing a service control function (SCF) either in the form of a service control point, SCP 17 (see FIG. 2) or an Adjunct 18. The Adjunct 18 is directly associated with an SSP 25 whilst the SCP 17 and SSP 25 communicate with each other via an extended common channel signalling (CCS) network 16 that may include signal transfer points (STP) 19. The SCP 17 may be associated with more than one SSP 25. Both the SCP 17 and Adjunct 18 provide a service logic execution environment (SLEE) 20 in which instances of one or more service logic programs (SLP) 21 can execute. The SLEE 20 and SLP 21 together provide service control functionality for providing services to the SSP 25.
Service logic running in an SCP or Adjunct will generally make use of subscriber information stored in a service data function (SDF) 22 that may be integral with the SCP/Adjunct or partially or wholly separate therefrom. The service data function (SDF), like the service control function (SCF) forms part of the service control subsystem of the PSTN. It may be noted that some or all of the service control function may be built into the PSTN switches themselves.
In operation, when the SSP 25 receives a call, it examines internal trigger conditions and, possibly, user information (eg dialed digits) to ascertain if the call requires a service to be provided by the service control subsystem 17, 18; the checking of trigger conditions may be carried out at several different points in call processing. Where the SSP 25 determines that a service is required it messages the service control subsystem (either SCP 17 or Adjunct 18) requesting the desired service and sending it a logic representation of the call in terms of its connectivity and call processing status. The service control subsystem then provides the requested service and this may involve either a single interaction between the SSP and service control subsystem or a session of interactions. A typical service is call forwarding which is a called-party service giving expression to an end-user requirement as simple as "if you call me on number X and it rings ten times, try calling number Y". In this case, it is the SSP local to the called end-user that triggers its associated SCP (or Adjunct) to provide this service; it will, of course, be appreciated that the SSP must be primed to know that the service is to be provided for a called number X.
In addition to the SCP 17 and Adjunct 18, the FIG. 2 network includes an intelligent peripheral (IP) 23 that has bearer-channel connectivity to one or more SSPs 25. The IP 23 provides resources needed to exchange information with an end user, such as voice announcements and DTMF digit collection capabilities (this type of non-signalling information intended to be passed over a bearer-channel to/from the end user is referred to below generally as "content"). These IP resources are managed and controlled by a resource control execution environment (RCEE) 26 of the IP 23 in response to input received from an SSP 25. Such input may result, for example, from the service control subsystem (SCP 17, Adjunct 18), during execution of an SLP 21, requiring a voice announcement to be played to an end user; in this case the service control subsystem passes this requirement to the SSP concerned which sets up a bearer channel to the IP 23 and commands the IP to play the required announcement. It is also possible to arrange for the service control subsystem to communicate directly over the CCS network with an IP rather than going though an SSP 25.
IP functionality and resources may also be provided within a service node (SN) which like an IP has bearer-channel connectivity to an SSP; however, an SN additionally includes a service node execution environment (SNEE) 28, similar to SLEE 20, for running service logic programs. An SN can thus provide a range of services virtually autonomously once an SSP has switched through a call to the SN; in particular, an SN is apt to provide services such as voice mail, automated attendant and fax server, all of which require substantial transfer of content to/from an end user. The IP functionality and resources of an SN are generally not under the exclusive control of the SNEE of the SN but can be used by remote SLEEs. To the extent that an SN can execute specific types of SLPs, it forms part of the service control subsystem of the network.
The network will also include an operation system (not shown) that has a general view of the network and its services and performs functions such as network monitoring and control.
The above-described model for the provision of IN services in a PSTN can also be mapped onto PLMNs (Public Land Mobile Networks) such as GSM and other mobile networks. Control signalling in the case of a mobile subscriber is more complex because in addition to all the usual signalling requirements, there is also a need to establish where a call to a mobile subscriber should be routed; however, this is not a very different problem from a number of called-party IN services in the PSTN. Thus in GSM, the service data function (SDF) is largely located in a system named a Home Location Register (HLR) and the service control function in a-system named a Visitor Location Register (VLR) that is generally associated on a one-to-one basis with each SSP (which in GSM terminology is called a Mobile Switching Centre, MSC).
Because subscribers are mobile, the subscriber profile is transported from the HLR to whichever VLR happens to be functionally closest to be mobile subscriber, and from there the VLR operates the (fixed) service using the subscriber profile and interacts with the SSP. The HLR and VLR thus constitute a service control subsystem similar to an SCP or Adjunct with their associated databases.
It is, of course, also possible to provide IN services in private telephone systems and, in this case, the service control function and service data function are generally either integrated into a PABX (Private Automatic Branch Exchange) or provided by a local computer. The service control subsystem, whilst present, may thus not be a physically distinct from the PABX.
The above-described general architectural framework for providing IN services has both strengths and flaws. Its main strength is that it works and many services have been successfully deployed, such as 800 number services, credit card calling, voicemail, and various call waiting and redirection services. However, despite years of standardisation, services are still implemented one-at-a-time on proprietary platforms and do not scale well. The approach has been based on large, fault-tolerant systems which provide services for hundreds of thousands or even millions of subscribers and take years to deploy. Furthermore, since the networks used to support these services also constitute the basic telephone infrastructure, anything attached to these networks must be rigorously vetted. Additionally, each country and operator tends to have local variations of the so-called standards making it difficult to supply standard products and thereby braking the dynamics of competition.
The World Wide Web
In contrast to the slow deliberate progress of the telephone infrastructure, the WWW has grown explosively from its inception in 1989 to become the primary electronic information distribution service in terms of spread, availability and richness of information content. Anyone can, for a modest outlay, become an information provider with a world-wide audience in a highly interconnected information architecture.
The WWW is a client-server application running over the Internet and using a client-server protocol which mandates only the simplest of exchanges between client and server. This protocol is HTTP (Hyper Text Transfer Protocol) which is optimised for use over TCP/IP networks such as the Internet; the HTTP protocol can, however, also be used over networks using different communication protocol stacks.
Since the availability of literature concerning the WWW has seen the same sort of growth as the WWW itself, a detailed description of the WWW, HTTP and the Internet will not be given herein. An outline description will, however, be given with attention being paid to certain features of relevance to the present invention.
The WWW uses the Internet for interconnectivity. Internet is a system that connects together networks on a worldwide basis. Internet is based on the TCP/IP protocol suite and provides connectivity to networks that also use TCP/IP. For an entity to have a presence on the Internet, it needs both access to a network connected to the Internet and an IP address. IP addresses are hierarchically structured. Generally an entity will be identified at the user level by a name that can be resolved into the corresponding IP address by the Domain Name System (DNS) of the Internet.
Operation of the WWW Referring now to FIG. 3 of the accompanying drawings, access to the Internet 30 may be by direct connection to a network that is itself directly or indirectly connected to the Internet; such an arrangement is represented by terminal 31 in FIG. 3 (this terminal may, for example, be a Unix workstation or a PC). Having a connection to the Internet of this form is known as having `network access`. Any entity that has network access to the Internet may act as a server on the Internet provided it has sufficient associated functionality; in FIG. 3, entity 32 with file store 37 acts as a server.
Many users of the WWW do not have network access to the Internet but instead access the Internet via an Internet service provider, ISP, 33 that does have network access. In this case; the user terminal 34 will generally communicate with the ISP 33 over the public telephone system using a modem and employing either SLIP (Serial Line Interface Protocol) or PPP (Point-to-Point Protocol). These protocols allow Internet packets to traverse ordinary telephone lines. Access to the Internet of this form is known as "dialup IP" access. With this access method, the user terminal 34 is temporarily allocated an IP address during each user session; however, since this IP address may differ between sessions, it is not practical for the entity 34 to act as a server.
A cornerstone of the WWW is its ability to address particular information resources by means of an Uniform Resource Identifier (URI) that will generally be either a Uniform Resource Locator (URL) that identifies a resource by location, or a Uniform Resource Name (URN) that can be resolved into an URL. By way of example, a full or "absolute" URL will comprise the following elements:
scheme--this is the access scheme to be used to access the resource of interest; PA1 host--the Internet host domain name or IP address; PA1 port--the host port for the (TCP) connection; PA1 abs-path--the absolute path of the resource on the host. PA1 scheme--http PA1 host--www.hp.com PA1 port--omitted (port 80 assumed) PA1 abs-path--Products.html PA1 GET--This method results in the retrieval of whatever information (in the form of an entity) is identified by the Request-URI. It is important to note that if the Request-URl refers to a data-producing process, it is the produced data which is returned as the entity in the response and not the source text of the process. PA1 POST--This method is used to request that the destination server accept the entity enclosed in the request as a new subordinate of the resource identified by the Request-URI. The POST method can be used for annotation of exiting resources, providing a message to a bulletin board, providing data to a data-handling process (for example, data produced as the result of submitting a form), and extending a database through an append operation. PA1 (a) during the course of a call involving a user telephone connected to said telephone network, determining conditions indicative that a said content resource is to be accessed; PA1 (b) where step (a) indicates that a said content resource is to be accessed, using at least a part of one of: PA1 mapping said predetermined code to the said known URI of the content resource associated with that predetermined code; and PA1 (d) utilising the URI derived in step (d) to access the required content resource over said computer network. PA1 (e) transferring content through said networks in at least one direction between said content resource and said telephone. PA1 said intelligent peripheral functionality is connected to a computer network that is generally accessible to users of the telephone network but logically distinct therefrom; PA1 said service switching point includes means for determining during call setup involving a user telephone connected to said bearer network, conditions indicative that a content-item access service is required involving accessing a content item provided at a particular URI on a server connected to said computer network, said content item having an associated predetermined code; PA1 said service control subsystem includes means responsive to the service switching point determining that said content-item access service is required, to form said predetermined code using at least a part of a number dialed from said user telephone; PA1 one of said service control subsystem and intelligent peripheral functionality has mapping means for mapping said predetermined code to the said particular URI of the content item to be accessed; and PA1 said intelligent peripheral functionality is operative to use the URI derived by said mapping means to access the required content item over said computer network and transfer it to said user telephone.
In fact, the `port` may be omitted in which case port 80 is assumed.
FIG. 4 of the accompanying drawings shows an example URL for the Hewlett-Packard products welcome page. In this case, the elements are:
The HTTP protocol is based on a request/response paradigm. Referring again to FIG. 3 of the drawings, given a particular URI identifying a resource 30 to be accessed, a client establishes a connection with the server 31 corresponding to the "host" element of the URI and sends a request to the server. This request includes a request method, and the "Request-URI" (which is generally just the absolute path of the resource on the server as identified by the "abs-path" element of the URI); the request may include additional data elements. The server 31 then accesses the resource 36 (here held on storage 37) and responds and this response may include an entity of a type identified by a MIME (Multipurpose Internet Mail Extensions) type also included in the response.
The two main request methods are:
In summary, the GET method can be used to directly retrieve data, or to trigger any process that will return an entity (which may either be data or a simply an indication of the result of running the process). The POST method is used for registering data and specifying this method is also effective to trigger a process in the server to handle the posted data appropriately.
The passing of information to a process triggered to run on a server using either the GET or POST method is currently done according to an interface called the Common Gateway interface (CGI). The receiving process is often written in a scripting language though this is not essential. Typically, the triggered server script is used for interfacing to a database to service a query included in a GET request. Another use, already referred to, is to append data associated with a POST request to a database.
Other important factors in the success of the WWW is the use of the HyperText Markup Language (HTML) for representing the makeup of documents transferred over the WWW, and the availability of powerful graphical Web browsers, such as Netscape and Mosaic, for interpreting such documents in a client terminal to present them to a user. Basically, HTML is used to identify each part of a document, such as a title, or a graphic, and it is then up to the browser running in the client terminal to decide how to display each document part. However, HTML is more than this--it also enables a URI and a request method to be associated with any element of a document (such as a particular word or an image) so that when a user points to and clicks on that element, the resource identified by the URI is accessed according to the scheme (protocol) and request method specified. This arrangement provides a hyperlink from one document to another. Using such hyperlinks, a user at a client terminal can skip effortlessly from one document downloaded from a server on one side of the world, to another document located on a server on the other side of the world. Since a document created by one author may include a hyperlink to a document created by another, an extremely powerful document cross-referring system results with no central bureaucratic control.
Hyperlinks are not the only intelligence that can be built into an HTML document. Another powerful feature is the ability to fill in a downloaded "Form" document on screen and then activate a `commit` graphical button in order to have the entered information passed to a resource (such as a database) designed to collect such information. This is achieved by associating the POST request method with the `commit` button together with the URI of the database resource; activating the `commit` button results in the entered information being posted to the identified resource where it is appropriately handled.
Another powerful possibility is the association of program code (generally scripts to be interpreted) with particular documents elements, such as graphical buttons, this code being executed upon the button being activated. This opens up the possibility of users downloading program code from a resource and then running the code.
It will be appreciated by persons skilled in the art that HTML is only one of several currently available scripting languages delivering the functionality outlined above and it may be expected that any serious Web browser will have built-in support for multiple scripting languages. For example, Netscape 2.0 supports HTML 3.0, Java and LiveScript (the latter being Netscape proprietary scripting Language).
The importance of the role of the graphical Web browser itself should not be overlooked. As well as the ability to support multiple scripting languages, a Web browser should provide built-in support for standard media types, and the ability to load and execute programs in the client, amongst other features. These browsers may be viewed as operating systems for WWW interaction.
WWW and the Telephone Network
It is possible to provide a telephony service over the Internet between connected terminals by digitising voice input and sending it over the Internet in discrete packets for reassembly at the receiving terminal. This is an example of a communication service on the Internet. Conversely, it is possible to point to a variety of information services provided over the telephone system, such as the Minitel system widely available in France. However, these encroachments into each anothers traditional territories pose no real threat to either the Internet or the public telephone system.
Of more interest are areas of cooperative use of the Internet and the telephone system. In fact, one such area has existed for some considerable time and has been outlined above with reference to FIG. 4, namely the use of a modem link over the PSTN from a user computer 34 to an Internet service provider 33 in order to obtain dialup IP access to the Internet. This cooperative use is of a very simple nature, namely the setting up of a bearer channel over the PSTN for subsequently generated Internet traffic; there is no true interaction between the Internet and the PSTN.
Another known example of the cooperative use of the Internet and PSTN are the services by which an Internet user with a sound card in his/her terminal computer can make a voice call to a standard telephone anywhere in the world. This is achieved by transferring digitised voice over the Internet to a service provider near the destination telephone; this service provider then connects into the local PSTN to access the desired phone and transfers across into the local PSTN the voice traffic received over the Internet. Voice input from the called telephone is handled in the reverse manner. Key to this service is the ability to identify the service provider local (in telephony charging terms) to the destination phone. This arrangement, whilst offering the prospect of competition for the telecom operators for long distance calls, is again a simple chaining together of the Internet and PSTN. It may, however, be noted that in this case it is necessary to provide at least a minimum of feedback to the Internet calling party on the progress of call set to the destination telephone over the PSTN local to that telephone; this feedback need only be in terms of whether or not the call has succeeded.
It is an object of the present invention to provide improved access for telephone users to information resources available on the Internet.